The present invention relates to a motorcycle tire suitable for off-road traveling, and more particularly to an off-road motorcycle tire having an improved cracking resistance.
Motorcycle tires for traveling on unpaved roads or rough terrain, e.g., motocross tires, generally have a block type tread pattern in which a plurality of blocks are formed in a tread portion, as disclosed for example in JP-A-2007-131111. These tires having a block pattern secure a traction and a cornering force to improve the steering stability by an edge effect of the blocks biting into a soft ground such as mud or sand.
As shown in FIG. 8, for example, a block “a” of these tires may be provided with a shallow groove “b” extending in the tire circumferential direction. Such a shallow groove “b” can increase the edge of the block “a” and moreover can accelerate water drainage and removal of mud on a hard or medium hard road.
In case of such a block “a”, however, a strain is easy to converge on an intersection portion “e” between a bottom surface “c” of the shallow groove “b” and an outer wall surface “d” of the block “a” and on both end portions “f” of the intersection portion “e” due to deformation of the block associated with contact and non-contact to the ground. Therefore, such a block “a” having a shallow groove “b” has a problem that cracks are easy to generate from these portions “e” and “f”.
Accordingly, it is an object of the present invention to provide an off-road motorcycle tire having an improved cracking resistance.
This and other objects of the present invention will become apparent from the description hereinafter.